JP2012018365A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device having good display quality.SOLUTION: A liquid crystal display device includes a first substrate, a second substrate, and a liquid crystal layer. The first substrate has a common electrode arranged over a first insulating substrate, an insulating film covering the common electrode, multiple pixel electrodes arranged on the insulating film to be opposed to the common electrode and having slits formed therein, and a first oriented film covering the respective pixel electrodes. The second substrate has, on an inner surface of a second insulating substrate opposed to the first substrate, a black matrix arranged over between the pixel electrodes, a color filter arranged over the respective pixel electrodes, and a second oriented film arranged over the color filter at the first substrate side. The liquid crystal layer is retained between the first substrate and the second substrate and has a first region located on between the pixel electrodes and a second region located on the pixel electrodes. When a phase difference value of the liquid crystal layer is defined as Δn*d wherein Δn is refractive index anisotropy of the liquid crystal layer and d is a thickness of the liquid crystal layer, the phase difference value of the first region is smaller than the phase difference value of the second region.

Description

  Embodiments described herein relate generally to a liquid crystal display device.

  Liquid crystal display devices are utilized in various fields as display devices for OA equipment such as personal computers and televisions, taking advantage of features such as light weight, thinness, and low power consumption. In recent years, liquid crystal display devices are also used as mobile terminal devices such as mobile phones, display devices such as car navigation devices and game machines. In particular, as the amount of information increases, the demand for higher definition increases, while the demand for higher brightness (or higher transmittance) increases in order to improve outdoor visibility.

  The liquid crystal display device includes an array substrate including switching elements, gate wirings, source wirings, pixel electrodes, and the like, and a counter substrate including a black matrix, a color filter, and the like. In such a liquid crystal display device, in order to increase luminance or transmittance, it is necessary to increase the light transmission area (hereinafter referred to as aperture ratio) of each pixel. Specifically, the switching element is reduced in size, In addition, it is necessary to reduce the widths of the gate wiring, the source wiring, and the black matrix.

  However, as the aperture ratio of a pixel increases, the influence of light leakage between adjacent pixels becomes obvious. In particular, when the angle at which the liquid crystal display device is observed (hereinafter referred to as the viewing angle) is changed, there is a possibility that a problem of color mixing in which the color changes occurs. More specifically, when the liquid crystal display device is viewed from the front (that is, when the viewing angle is 0 °), the liquid crystal display device is viewed from an oblique direction (that is, when the viewing angle is 0 °). In the case of ≠ 0 °, the light transmitted through the color filters of different colors of the adjacent pixels is also observed at the same time, so that the color changes and the display quality may be deteriorated.

JP 2005-195927 A

  An object of the present embodiment is to provide a liquid crystal display device with good display quality.

According to this embodiment,
A plurality of first insulating substrates; a common electrode disposed above the first insulating substrate; an insulating film covering the common electrodes; and a plurality of slits formed on the insulating film so as to face the common electrodes and to form a slit. A first substrate having a first alignment film covering each of the pixel electrodes, a second insulating substrate, and an inner surface of the second insulating substrate facing the first substrate. A black matrix disposed immediately above each of the pixel electrodes, a color filter disposed immediately above each of the pixel electrodes, and a second alignment film disposed on the first substrate side of the color filter. Two substrates, a first region that is held between the first substrate and the second substrate, and is located immediately above the pixel electrodes; a second region that is located immediately above the pixel electrodes; A liquid crystal layer containing When the refractive index anisotropy of the crystal layer is Δn, the thickness of the liquid crystal layer is d, and the retardation value of the liquid crystal layer is defined by Δn · d, the retardation value of the first region is the second retardation value. A liquid crystal display device characterized by being smaller than the retardation value of the region is provided.

FIG. 1 is a plan view schematically showing the configuration of the liquid crystal display device according to the present embodiment. FIG. 2 is a diagram schematically showing a configuration and an equivalent circuit of the liquid crystal display panel shown in FIG. FIG. 3 is a schematic plan view of an example of the pixel structure of the array substrate shown in FIG. 2 as viewed from the counter substrate side. FIG. 4 is a diagram schematically showing a cross-sectional structure of a liquid crystal display panel in which the pixel shown in FIG. 3 is cut along the line AB. FIG. 5 is a diagram for explaining the relationship between the axial angles of various optical elements applied in this embodiment, and is a top view when the liquid crystal display panel is observed from the counter substrate side. FIG. 6 is a diagram for explaining the operation principle in the liquid crystal display device of the present embodiment. FIG. 7 is a cross-sectional view schematically showing the liquid crystal display panel in the first configuration example of the present embodiment. FIG. 8 is a diagram illustrating a calculation result of transmitted light intensity at each viewing angle with respect to the phase difference value (Δn × d). FIG. 9 is a cross-sectional view schematically showing the liquid crystal display panel LPN in the second configuration example of the present embodiment. FIG. 10 is a cross-sectional view schematically showing a liquid crystal display panel LPN in the third configuration example of the present embodiment. FIG. 11 is a schematic plan view for explaining the shape of the protrusion applicable in the present embodiment. FIG. 12 is a schematic plan view for explaining another shape of the protrusion applicable in the present embodiment.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to components that exhibit the same or similar functions, and duplicate descriptions are omitted.

  FIG. 1 is a plan view schematically showing a configuration of a liquid crystal display device 1 in the present embodiment.

  That is, the liquid crystal display device 1 includes an active matrix type liquid crystal display panel LPN, a drive IC chip 2 connected to the liquid crystal display panel LPN, a flexible wiring board 3, and the like.

  The liquid crystal display panel LPN is held between an array substrate AR as a first substrate, a counter substrate CT as a second substrate disposed to face the array substrate AR, and the array substrate AR and the counter substrate CT. And a liquid crystal layer (not shown). The array substrate AR and the counter substrate CT are bonded together by a seal material SE. The liquid crystal layer is held on the inner side surrounded by the sealing material SE in the cell gap formed between the array substrate AR and the counter substrate CT. For example, the seal material SE is formed in a substantially rectangular frame shape between the array substrate AR and the counter substrate CT and forms a closed loop.

  Such a liquid crystal display panel LPN includes a substantially rectangular active area ACT for displaying an image on the inner side surrounded by the seal material SE. This active area ACT is composed of a plurality of pixels PX arranged in an m × n matrix (where m and n are positive integers). The driving IC chip 2 and the flexible wiring board 3 are mounted on the array substrate AR in the peripheral area PRP outside the active area ACT.

  FIG. 2 is a diagram schematically showing a configuration and an equivalent circuit of the liquid crystal display panel LPN shown in FIG. Here, the array substrate AR of the liquid crystal display panel LPN includes a pixel electrode PE and a common electrode CE, and a horizontal electric field (that is, substantially parallel to the main surface of the substrate) formed between the pixel electrode PE and the common electrode CE. A configuration in which a fringe field switching (FFS) mode for switching liquid crystal molecules constituting the liquid crystal layer LQ is mainly used will be described.

  In the active area ACT, the array substrate AR includes n gate wirings G (G1 to Gn) and n capacitance lines C (C1 to Cn) that extend along the X direction, and Y that is substantially orthogonal to the X direction. M source lines S (S1 to Sm) extending along the direction, m × n switching elements SW arranged in each pixel PX and electrically connected to the gate lines G and the source lines S, There are provided m × n pixel electrodes PE disposed in the pixel PX and electrically connected to the switching element SW, a common electrode CE which is a part of the capacitor line C and faces the pixel electrode PE, and the like. For example, the storage capacitor Cs is formed between the capacitor line C and the pixel electrode PE. The liquid crystal layer LQ is interposed between the pixel electrode PE and the common electrode CE.

  Each gate line G is drawn outside the active area ACT and is connected to the first drive circuit GD. Each source line S is drawn outside the active area ACT and connected to the second drive circuit SD. Each capacitance line C is drawn outside the active area ACT and connected to the third drive circuit CD. The first drive circuit GD, the second drive circuit SD, and the third drive circuit CD are formed on the array substrate AR and connected to the drive IC chip 2.

  In the illustrated example, the drive IC chip 2 is mounted on the array substrate AR outside the active area ACT of the liquid crystal display panel LPN. In addition, illustration of a flexible wiring board is abbreviate | omitted and the terminal T for connecting a flexible wiring board is formed in array board | substrate AR. These terminals T are connected to the driving IC chip 2 through various wirings.

  FIG. 3 is a schematic plan view of an example of the structure of the pixel PX in the array substrate AR shown in FIG. 2 as viewed from the counter substrate CT side.

  The gate line G extends substantially linearly along the X direction. The source line S extends substantially linearly along the Y direction. The switching element SW is disposed in the vicinity of the intersection of the gate line G and the source line S, and is configured by, for example, a thin film transistor (TFT). The switching element SW includes a semiconductor layer SC. The semiconductor layer SC can be formed of, for example, polysilicon or amorphous silicon, and is formed of polysilicon here.

  The gate electrode WG of the switching element SW is located immediately above the semiconductor layer SC and is electrically connected to the gate wiring G (in the illustrated example, the gate electrode WG is formed integrally with the gate wiring G. ) The source electrode WS of the switching element SW is electrically connected to the source line S (in the illustrated example, the source electrode WS is formed integrally with the source line S). The drain electrode WD of the switching element SW is electrically connected to the pixel electrode PE.

  The capacitance line C extends in the X direction. The capacitor line C includes a common electrode CE formed corresponding to each pixel PX, and extends above at least a part of the source line S. The pixel electrode PE is disposed above the common electrode CE. The pixel electrode PE is formed in an island shape corresponding to the pixel shape in the pixel PX, for example, a substantially square shape. Each pixel electrode PE is connected to the drain electrode WD of the switching element SW.

  A slit PSL is formed in such a pixel electrode PE. In the illustrated example, the slit PSL extends in a straight line in the Y direction. That is, the extending direction of the slit PSL is substantially parallel to the direction in which the source wiring S extends. The slit PSL is formed on the common electrode CE. With such a slit shape, a single domain is formed in each pixel PX.

  In such an array substrate AR, a columnar spacer SP that forms a cell gap between the array substrate AR and the counter substrate CT is disposed immediately above the wiring portions such as the gate wiring G, the source wiring S, and the switching element SW. ing. In the illustrated example, the columnar spacer SP is disposed immediately above the gate wiring G.

  FIG. 4 is a diagram schematically showing a cross-sectional structure of a liquid crystal display panel LPN obtained by cutting the pixel PX shown in FIG. 3 along the line AB.

  That is, the array substrate AR is formed by using a first insulating substrate 20 having a light transmission property such as a glass plate. The array substrate AR includes a switching element SW on the inner surface of the first insulating substrate 20 (that is, the surface facing the counter substrate CT). The switching element SW shown here is a top-gate thin film transistor. The semiconductor layer SC is disposed on the first insulating substrate 20. Such a semiconductor layer SC is covered with the gate insulating film 21. The gate insulating film 21 is also disposed on the first insulating substrate 20. Note that an undercoat layer may be disposed as an insulating film between the first insulating substrate 20 and the semiconductor layer SC.

  The gate electrode WG of the switching element SW is disposed on the gate insulating film 21 and is located immediately above the semiconductor layer SC. The gate wiring G is also disposed on the gate insulating film 21. The gate electrode WG and the gate wiring G are covered with the first interlayer insulating film 22. The first interlayer insulating film 22 is also disposed on the gate insulating film 21. The gate insulating film 21 and the first interlayer insulating film 22 are formed of an inorganic material such as silicon nitride (SiN).

  The source electrode WS and the drain electrode WD of the switching element SW are disposed on the first interlayer insulating film 22. The source electrode WS and the drain electrode WD are in contact with the semiconductor layer SC through contact holes that penetrate the gate insulating film 21 and the first interlayer insulating film 22. A source wiring (not shown) is also disposed on the first interlayer insulating film 22. The gate electrode WG, the source electrode WS, and the drain electrode WD are formed of a conductive material such as molybdenum, aluminum, tungsten, or titanium.

  The source electrode WS and the drain electrode WD are covered with the second interlayer insulating film 23. The second interlayer insulating film 23 is also disposed on the first interlayer insulating film 22. The capacitor line C including the common electrode CE is disposed on the second interlayer insulating film 23. The common electrode CE and the capacitor line C are covered with the third interlayer insulating film 24. The third interlayer insulating film 24 is also disposed on the second interlayer insulating film 23. The first interlayer insulating film 23 and the second interlayer insulating film are made of, for example, a resin material.

  The columnar spacer SP is disposed on the third interlayer insulating film 24. This columnar spacer SP is made of, for example, a resin material.

  The pixel electrode PE is disposed on the third interlayer insulating film 24. The pixel electrode PE is connected to the drain electrode WD through a contact hole that penetrates the second interlayer insulating film 23 and the third interlayer insulating film 24. In the pixel electrode PE, a slit PSL facing the common electrode CE is formed. Such a pixel electrode PE faces the common electrode CE via the second interlayer insulating film 24.

  The common electrode CE, the capacitor line C, and the pixel electrode PE are both formed of a light-transmitting conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The pixel electrode PE, the columnar spacer SP, and the second interlayer insulating film 24 are covered with a first alignment film 25. That is, the first alignment film 25 is disposed on the surface in contact with the liquid crystal layer LQ of the array substrate AR.

  On the other hand, the counter substrate CT is formed using a second insulating substrate 30 having optical transparency such as a glass plate. The counter substrate CT includes, on the inner surface of the second insulating substrate 30 (that is, the surface facing the array substrate AR), a black matrix 31 for partitioning each pixel PX, and a color filter 32 disposed in each pixel PX. ing.

  The black matrix 31 is disposed in the active area ACT on the second insulating substrate 30. More specifically, the black matrix 31 is disposed so as to be located immediately above wiring portions such as the gate wiring G, the source wiring S, and the switching element SW provided on the array substrate AR. Such a black matrix 31 is formed in a lattice shape or a stripe shape. The black matrix 31 is made of, for example, a black-colored resin material or a light shielding metal material such as chromium (Cr).

  The color filter 32 is disposed in the active area ACT on the second insulating substrate 30. A part of the color filter 32 is stacked on the black matrix 31. The color filter 32 includes a red color filter disposed corresponding to the red pixel, a blue color filter disposed corresponding to the blue pixel, and a green color filter disposed corresponding to the green pixel. included. These red color filter, blue color filter, and green color filter are formed of resin materials colored in respective colors.

  In the liquid crystal mode using the lateral electric field as described above, it is desirable that the surface of the counter substrate CT that is in contact with the liquid crystal layer LQ is flat, and the counter substrate CT further includes irregularities on the surfaces of the black matrix 31 and the color filter 32. An overcoat layer 33 for flattening is provided. Such an overcoat layer 33 is formed of, for example, a transparent resin material.

  The overcoat layer 33 is covered with a second alignment film 34. That is, the second alignment film 34 is disposed on the surface in contact with the liquid crystal layer LQ of the counter substrate CT. The first alignment film 25 and the second alignment film 34 are made of polyimide, for example.

  The array substrate AR and the counter substrate CT as described above are arranged so that the first alignment film 25 and the second alignment film 34 face each other. At this time, the columnar spacers SP are arranged between the array substrate AR and the counter substrate CT, thereby forming a predetermined cell gap. The array substrate AR and the counter substrate CT are bonded together with a sealing material (not shown) in a state where a predetermined cell gap is formed.

  The liquid crystal layer LQ is composed of a liquid crystal composition sealed in a cell gap formed between the first alignment film 25 of the array substrate AR and the second alignment film 34 of the counter substrate CT.

  A first polarizing plate PL1 is disposed on one outer surface of the liquid crystal display panel LPN, that is, on the outer surface of the first insulating substrate 20 constituting the array substrate AR. The first polarizing plate PL1 is fixed by being adhered to the outer surface of the first insulating substrate 20.

  A second polarizing plate PL2 is disposed on the other outer surface of the liquid crystal display panel LPN, that is, the outer surface of the second insulating substrate 30 constituting the counter substrate CT. The second polarizing plate PL2 is fixed by being adhered to the outer surface of the second insulating substrate 30. Note that one or more retardation plates may be disposed between the second insulating substrate 30 and the second polarizing plate PL2.

  FIG. 5 is a diagram for explaining the relationship between the axial angles of various optical elements applied in this embodiment, and is a top view when the liquid crystal display panel LPN is observed from the counter substrate CT side, that is, from above. is there.

  In the liquid crystal display panel LPN, the slit PSL formed in each pixel electrode PE extends in the Y direction as described above. The first alignment film 25 provided in the array substrate AR is rubbed in the θ direction. That is, the rubbing direction R1 of the first alignment film 25 is the θ direction. The extending direction (Y direction) of the slit PSL is a direction slightly inclined counterclockwise (positive direction) with respect to the θ direction. Here, the slit PSL corresponds to a direction shifted by an angle of 5 to 10 degrees counterclockwise with respect to the θ direction. In other words, the θ direction is a direction shifted by an angle of 5 to 10 ° clockwise (negative direction) from the Y direction.

  The second alignment film 34 provided on the counter substrate CT is parallel to the rubbing direction R1 of the first alignment film 25, but is rubbed in the opposite direction. That is, the rubbing direction R2 of the second alignment film 34 is the (θ + 180 °) direction.

  The first polarizing plate PL1 has a first absorption axis A1 parallel to the rubbing direction R1 of the first alignment film 25. That is, the first absorption axis A1 is parallel to the θ direction. The second polarizing plate PL2 has a second absorption axis A2 orthogonal to the first absorption axis A1. That is, the second absorption axis A2 is parallel to the (θ + 90 °) direction.

  FIG. 6 is a diagram for explaining the operation principle in the liquid crystal display device of the present embodiment. Here, description will be made with reference to a cross section of the liquid crystal display panel LPN in a direction (θ + 90 °) parallel to the second absorption axis A2. Here, only the configuration necessary for the description is illustrated.

  In the liquid crystal display device of this embodiment, the pixel PX1 on the left side in the drawing shows an OFF state in which no electric field is formed between the pixel electrode PE1 and the common electrode CE, and the pixel PX2 on the right side in the drawing is shown. FIG. 2 illustrates an ON state in which an electric field (fringe electric field) FE is formed between the pixel electrode PE2 and the common electrode CE via the slit PSL.

  In the pixel PX1 in the OFF state, the alignment axis of the liquid crystal molecules LM homogeneously aligned in the rubbing direction R1 of the first alignment film and the rubbing direction R2 of the second alignment film in the liquid crystal layer LQ is the first absorption axis of the first polarizing plate PL1. While being parallel to A1, it is orthogonal to the second absorption axis A2 of the second polarizing plate PL2. In this OFF state, the linearly polarized light emitted from the backlight BL and transmitted through the first polarizing plate PL1 is absorbed by the second polarizing plate PL2 after passing through the liquid crystal display panel LPN, so that black display is obtained.

  On the other hand, in the pixel PX2 in the ON state, some liquid crystal molecules LM are modulated under the influence of the fringe electric field FE, and the alignment axes thereof are the first absorption axis A1 of the first polarizing plate PL1 and the second polarizing plate PL2. 2 Deviation from the absorption axis A2. In this ON state, the linearly polarized light that has passed through the first polarizing plate PL1 passes through the liquid crystal display panel LPN and then passes through the second polarizing plate PL2, so that white display is performed. Thereby, the normally black mode is realized.

  By the way, when one adjacent pixel PX1 is in an OFF state and the other pixel PX2 is in an ON state, the potential difference between the pixel electrode PE1 of the pixel PX1 and the pixel electrode PE2 of the pixel PX2 is as illustrated. An undesired lateral electric field NE is generated. That is, the horizontal electric field NE is formed across the pixel PX1 in the OFF state and the pixel PX2 in the ON state. For this reason, the liquid crystal molecules LMX located immediately above the pixel PX1 and the pixel PX2 are modulated under the influence of the undesired lateral electric field NE.

  In particular, as in the illustrated example, in the configuration in which the pixel electrode PE1 and the pixel electrode PE2 are disposed above the common electrode CE via the second interlayer insulating film 24, the pixel electrode PE2 and the common electrode CE are disposed between the pixel electrode PE2 and the common electrode CE. The influence of the transverse electric field NE that crosses the liquid crystal layer LQ is more dominant between the pixel electrode PE2 and the pixel electrode PE1 than the influence of the electric field. For this reason, in such a configuration, it is not possible to ignore the influence caused by the modulation of the liquid crystal molecules LMX between the pixels due to an undesired lateral electric field NE.

  For example, in the configuration in which the common electrode CE is disposed above the pixel electrode PE1 and the pixel electrode PE2 via the insulating layer in the array substrate AR, the common electrode CE disposed across the pixels is closer to the liquid crystal layer LQ. Therefore, when the pixel PX1 is in the OFF state and the pixel PX2 is in the ON state, the influence of the transverse electric field NE across the liquid crystal layer LQ is small between the pixel electrode PE2 and the pixel electrode PE1, and the pixel electrode PE2 The influence of the electric field between the common electrode CE is dominant. For this reason, in the case of such a configuration, even if the liquid crystal molecules LMX between the pixels are modulated by an undesired lateral electric field NE, the influence of the liquid crystal molecules LMX can be almost ignored.

  Consider a case where the pixel PX1 is a green pixel including the green color filter 32G and the pixel PX2 is a red pixel including the red color filter 32R. When displaying red, the pixel PX1 is in an OFF state (that is, a light non-transmission state), and the pixel PX2 is in an ON state (that is, a light transmission state). When the liquid crystal display panel LPN is observed from the front direction, only the light beam that has passed through the red color filter 32R of the pixel PX2 is observed, so that it is visually recognized as red.

However, when the viewing angle is enlarged and the liquid crystal display panel LPN is observed from an oblique direction, the liquid crystal layer LQ immediately below the black matrix 31 is modulated under the influence of an undesired lateral electric field NE, and is caused by a birefringence phenomenon. Has the effect of transmitting light. The intensity I of the transmitted light that passes through the liquid crystal display panel LPN is defined by the product of the refractive index anisotropy (Δn) of the liquid crystal layer LQ induced by the electric field and the thickness or optical path length (d) of the liquid crystal layer LQ. It is proportional to the square of the sine function of the division term (Δn × d / λ) of the phase difference value (Δn × d) and the wavelength (λ), that is, sin ² (πΔn × d / λ). In the oblique direction, the substantial optical path length is larger than that in the front direction, so that the phase difference value (Δn × d) is further increased, and the transmitted light intensity is increased. When the phase difference value (Δn × d) is zero, the transmitted light intensity is also zero.

  That is, when observed from an oblique direction, not only the light beam that has passed through the red color filter 32R of the pixel PX2 but also the light beam that has passed through the green color filter 32G from the pixel PX1 is observed at the same time, so that red is mixed with green. A color mixing phenomenon occurs. When such a color mixing phenomenon occurs, a color different from the normal color is displayed depending on the viewing angle.

  While the liquid crystal mode using the horizontal electric field has the advantage that a wider viewing angle is possible compared to the TN mode using the vertical electric field, the liquid crystal mode can increase the viewing angle due to the color mixing phenomenon as described above. It is required to suppress the accompanying color change.

  Therefore, in the present embodiment, the phase difference value of the first region of the liquid crystal layer LQ positioned immediately above the pixel electrodes EP is equal to the phase difference value of the second region of the liquid crystal layer LQ positioned directly above the pixel electrodes EP. Is set smaller than. Thereby, it is possible to reduce the transmitted light intensity of the light transmitted through the first region, to suppress color mixing when the viewing angle is enlarged, and to enlarge the viewing angle at which the color does not change. Therefore, it is possible to provide a liquid crystal display device with good display quality.

  Hereinafter, more specific configuration examples 1 to 3 will be described.

First, configuration example 1 of the present embodiment will be described.
FIG. 7 is a cross-sectional view schematically showing the liquid crystal display panel LPN in the first configuration example of the present embodiment. FIG. 7 is a cross-sectional view of the liquid crystal display panel LPN along the X direction in which the gate line G extends. The pixel PX1 corresponds to a green pixel and the pixel PX2 corresponds to a red pixel.

  The illustrated liquid crystal display panel LPN is configured such that the center of the black matrix 31 formed on the counter substrate CT is located immediately above the center of the source wiring S formed on the array substrate AR.

  In the array substrate AR, adjacent pixels PX1 and PX2 across the source line S include pixel electrodes PE1 and PE2, respectively. A first protrusion PR1 is disposed between the pixel PX1 and the pixel PX2. In the illustrated example, the first protrusion PR1 is provided on the array substrate AR and protrudes toward the counter substrate CT. The first protrusion PR1 is disposed between the pixel electrode PE1 and the pixel electrode PE2. In the illustrated example, the first protrusion PR1 is formed on the second interlayer insulating film 24, and part of the first protrusion PR1 is formed on the pixel electrode PE1 and the pixel. It overlaps with the electrode PE2. That is, the first protrusion PR1 is located immediately above the source line S and is located directly below the black matrix 31. Such a first protrusion PR1 is covered with the first alignment film 25 in the same manner as the columnar spacers SP formed on the second interlayer insulating film 24.

  The first protrusion PR1 is formed of an insulating material, for example, a photosensitive resin material. Such a first protrusion PR1 can be formed in the same process using the same resin material as the columnar spacer SP.

  However, the height H1 of the first protrusion PR1 is not necessarily the same as the height SPH of the columnar spacer SP. Here, the height H1 of the first protrusion PR1 corresponds to a distance along the normal direction from the upper surface of the second interlayer insulating film 24 to the apex of the first protrusion PR1, and the height SPH of the columnar spacer SP is This corresponds to the distance along the normal direction from the upper surface of the two interlayer insulating film 24 to the apex of the columnar spacer SP.

  In the illustrated example, the height H1 of the first protrusion PR1 is lower than the height SPH of the columnar spacer SP (H1 <SPH). While the liquid crystal layer LQ is not interposed between the columnar spacer SP and the counter substrate CT, the liquid crystal layer LQ is interposed between the first protrusion PR1 and the counter substrate CT. As described above, when the height H1 of the first protrusion PR1 is different from the height SPH of the columnar spacer SP, the first protrusion PR1 and the columnar spacer SP are used by a method such as halftone exposure of a photosensitive resin material. Can be formed collectively.

  According to such a first configuration example, the first region LQ1 of the liquid crystal layer LQ located immediately above the pixel electrode PE1 and the pixel electrode PE2 has the thickness d1, and the pixel electrode PE1 (or the pixel electrode) The second region LQ2 of the liquid crystal layer LQ located immediately above PE2) has a thickness d2, and the thickness d1 is smaller than the thickness d2 (d2> d1). Here, for example, the thickness d1 is set to ½ of the thickness d2.

  Specifically, for example, the thickness d2 of the second region LQ2 is 4 μm, and the thickness d1 of the first region LQ1 is 2 μm. In this case, in consideration of the refractive index anisotropy of the first region LQ1 of the liquid crystal layer LQ induced by an undesired lateral electric field NE between the adjacent pixels PX1 and PX2, the phase difference in the first region LQ1 is considered. The value (Δn × d1) is about 50 nm.

  If the first protrusion PR1 is not provided, the thickness d1 of the first region LQ1 is substantially equal to the thickness d2 of the second region LQ2. In this case, the phase difference value (Δn × d1) in the first region LQ1 induced by the undesired lateral electric field NE between the adjacent pixels PX1 and PX2 is about 100 nm. That is, when the first protrusion PR1 is provided, the phase difference value of the first region LQ1 can be reduced compared to the case where the first protrusion PR1 is not provided.

  As a matter of course, in each of the pixel PX1 and the pixel PX2, the phase difference value (Δn × d2) in the second region LQ2 induced by the fringe electric field is the position in the first region LQ1 when the first protrusion PR1 is provided. It is larger than the phase difference value (Δn × d1).

As described above, since the transmitted light intensity I of the light transmitted through the liquid crystal layer LQ is proportional to sin ² (πΔn × d / λ), the transmitted light intensity I increases as the phase difference value (Δn × d) increases. . When the transmitted light intensity at each viewing angle with respect to the phase difference value (Δn × d) was calculated based on the light transmitted through the green pixel (λ = 550 nm), the result shown in FIG. 8 was obtained.

  When the first protrusion PR1 is provided and the phase difference value (Δn × d1) in the first region LQ1 is 50 nm, the phase difference value (Δn × d1) in the first region LQ1 is 100 nm without providing the first protrusion PR1. When the transmitted light intensity at each viewing angle is compared, the former case has been confirmed to be able to reduce the transmitted light intensity to about ¼ compared to the latter case.

  According to such a first configuration example, by providing the first protrusion PR1, the thickness d1 of the first region LQ1 of the liquid crystal layer LQ can be reduced, and the viewing angle is increased from 0 ° to 80 °. Even the color mixture was not visible. In the case where the first protrusion PR1 was not provided, the color mixture was visually recognized when the viewing angle was increased to 30 ° or more.

Next, configuration example 2 of the present embodiment will be described.
FIG. 9 is a cross-sectional view schematically showing the liquid crystal display panel LPN in the second configuration example of the present embodiment. In addition, about the same structure as the 1st structural example shown in FIG. 7, the same referential mark is attached | subjected and detailed description is abbreviate | omitted.

  The second configuration example shown in FIG. 9 is different from the first configuration example shown in FIG. 7 in that the counter substrate CT includes a second projection PR2 instead of the first projection PR1. ing.

  That is, the second protrusion PR2 is disposed between the pixel PX1 and the pixel PX2. The second protrusion PR2 is provided on the counter substrate CT and protrudes toward the array substrate AR. The second protrusion PR2 is disposed immediately above the pixel electrode PE1 and the pixel electrode PE2, and overlaps the black matrix 31 in the illustrated example. That is, the second protrusion PR2 is located immediately above the source line S and is located directly below the black matrix 31. The second protrusion PR2 is covered with the second alignment film 34.

  The second protrusion PR2 is formed of an insulating material, for example, a photosensitive resin material. More specifically, for example, the second protrusion PR2 is configured as a stacked body of a plurality of color filters 32. Such a second protrusion PR2 can be formed in the same process using the same resin material as that of the color filter 32. Further, at least a part of the second protrusion PR2 may be formed of the same resin material as the overcoat layer 33.

  In the illustrated example, the second protrusion PR2 includes a red color filter 32R stacked on the black matrix 31, a green color filter 32G stacked on the red color filter 32R, and an overcoat stacked on the green color filter 32G. It is configured as a laminate of layers 33. A liquid crystal layer LQ is interposed between the second protrusion PR2 and the array substrate AR.

  In such a second configuration example, as in the first configuration example, the thickness d1 of the liquid crystal layer LQ in the first region LQ1 is smaller than the thickness d2 of the second region LQ2 (d2> d1). Here, for example, the thickness d1 is set to about 3/4 of the thickness d2. In this case, in consideration of the refractive index anisotropy of the first region LQ1 of the liquid crystal layer LQ induced by an undesired lateral electric field NE between the adjacent pixels PX1 and PX2, the phase difference in the first region LQ1 is considered. The value (Δn × d1) is about 75 nm.

  When the second protrusion PR2 is provided and the phase difference value (Δn × d1) in the first region LQ1 is 75 nm, the phase difference value (Δn × d1) in the first region LQ1 is 100 nm without the second protrusion PR2. When the transmitted light intensity at each viewing angle is compared with the case where, as is clear from the results shown in FIG. 8, the transmitted light is about ½ in the former case compared to the latter case. It was confirmed that the strength could be reduced.

Next, configuration example 3 of the present embodiment will be described.
FIG. 10 is a cross-sectional view schematically showing a liquid crystal display panel LPN in the third configuration example of the present embodiment. In addition, about the same structure as the 1st structural example shown in FIG. 7, the same referential mark is attached | subjected and detailed description is abbreviate | omitted.

  The third configuration example shown in FIG. 10 is different from the first configuration example shown in FIG. 7 in that the counter substrate CT includes a second projection PR2 in addition to the first projection PR1. ing.

  That is, the first protrusion PR1 and the second protrusion PR2 are disposed between the pixels PX1 and PX2 and face each other. The first protrusion PR1 is provided on the array substrate AR and protrudes toward the counter substrate CT. The second protrusion PR2 is provided on the counter substrate CT and protrudes toward the array substrate AR. The details of the first protrusion PR1 and the second protrusion PR2 are as described in the first configuration example and the second configuration example, respectively. That is, the first protrusion PR1 and the second protrusion PR2 are located immediately above the source line S and located immediately below the black matrix 31. The first protrusion PR1 is covered with the first alignment film 25, and the second protrusion PR2 is covered with the second alignment film. In the illustrated example, a liquid crystal layer LQ is interposed between the first protrusion PR1 and the second protrusion PR2.

  Also in the third configuration example, as in the first configuration example, the thickness d1 of the liquid crystal layer LQ in the first region LQ1 is smaller than the thickness d2 of the second region LQ2 (d2> d1). Here, for example, the thickness d1 is set to about ¼ of the thickness d2. In this case, in consideration of the refractive index anisotropy of the first region LQ1 of the liquid crystal layer LQ induced by an undesired lateral electric field NE between the adjacent pixels PX1 and PX2, the phase difference in the first region LQ1 is considered. The value (Δn × d1) is about 25 nm.

  When the first projection PR1 and the second projection PR2 are provided and the phase difference value (Δn × d1) in the first region LQ1 is 25 nm, the first projection LPR1 and the second projection PR2 are not provided in the first region LQ1. When the transmitted light intensity at each viewing angle is compared in the case where the phase difference value (Δn × d1) is 100 nm, as is clear from the results shown in FIG. 8, the former case is compared with the latter case. Thus, it was confirmed that the transmitted light intensity can be reduced to about 1/16.

  In the first to third configuration examples of the present embodiment described above, the case where the thickness d1 in the first region LQ1 of the liquid crystal layer LQ is not zero has been described, but at least one of the first protrusion PR1 and the second protrusion PR2 is used. Thus, the thickness d1 may be 0 um. That is, in this case, the liquid crystal layer LQ does not intervene immediately below the black matrix 31. As a result, the phase difference value (Δn × d) of the liquid crystal layer LQ becomes zero regardless of the influence of the viewing angle and the undesired lateral electric field NE, and the transmitted light intensity becomes zero, that is, it is possible to completely block light. .

  In the first to third configuration examples of the present embodiment described above, at least one of the first protrusion PR1 and the second protrusion PR2 may be formed of a light-shielding material such as a black material. Thereby, when the viewing angle is enlarged, the transmitted light intensity of the light that has passed through the liquid crystal layer LQ can be reduced, and at least one of the first protrusion PR1 and the second protrusion PR2 can be shielded.

  11 and 12 are schematic plan views for explaining the shape of the protrusion PR (first protrusion PR1 or second protrusion PR2) applicable in the present embodiment. Here, a view when the liquid crystal display panel LPN is observed from the counter substrate CT side is shown. As shown in the figure, the projection PR is located immediately above the source line S.

  In particular, in the example shown in FIG. 11, the protrusion PR is linear (or continuous) between the pixel electrode PE1 and the pixel electrode PE2 adjacent in the X direction substantially parallel to the Y direction in which the source wiring S extends. ). By providing the projection PR having such a shape, it is possible to reduce the influence of the modulation of the liquid crystal layer LQ due to an undesired lateral electric field between pixels adjacent in the X direction.

  In the example shown in FIG. 12, the protrusion PR is partially (or discontinuously) arranged substantially parallel to the Y direction in which the source wiring S extends. In particular, the protrusion PR is disposed at the center portion between the pixel electrode PE1 and the pixel electrode PE2 adjacent in the X direction, but is interrupted along the Y direction. By providing the projection PR having such a shape, it is possible to reduce the influence of the modulation of the liquid crystal layer LQ due to an undesired lateral electric field between pixels adjacent in the X direction, as in the above example. In addition, it is possible to secure a path that allows the liquid crystal layer LQ to spread in the X direction. For example, when the liquid crystal material is vacuum-injected from the liquid crystal injection port or when the array substrate AR and the counter substrate CT are bonded to each other after the liquid crystal material is dropped inside the closed loop seal material, the liquid crystal material is Since the protrusion PR can spread and move in the X direction through the interrupted portion, the manufacturing time can be expected to be shortened.

  As described above, according to this embodiment, it is possible to provide a liquid crystal display device with good display quality.

  In addition, this invention is not limited to the said embodiment itself, In the stage of implementation, it can change and implement a component within the range which does not deviate from the summary. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device LPN ... Liquid crystal display panel AR ... Array substrate CT ... Opposite substrate SE ... Sealing material ACT ... Active area PX ... Pixel PE ... Pixel electrode CE ... Common electrode LQ ... Liquid crystal layer LQ1 ... 1st area | region LQ2 ... 2nd Region LM ... Liquid crystal molecule PR ... Projection PR1 ... First projection PR2 ... Second projection SP ... Columnar spacer 31 ... Black matrix 32 ... Color filter 33 ... Overcoat layer BL ... Backlight

Claims (8)

A plurality of first insulating substrates; a common electrode disposed above the first insulating substrate; an insulating film covering the common electrodes; and a plurality of slits formed on the insulating film so as to face the common electrodes and to form a slit. A first substrate comprising: a pixel electrode; and a first alignment film covering each of the pixel electrodes;
A second insulating substrate; a black matrix disposed directly between the pixel electrodes on an inner surface of the second insulating substrate facing the first substrate; and a color filter disposed immediately above each of the pixel electrodes; A second alignment film disposed on the first substrate side of the color filter, and a second substrate,
A liquid crystal layer that is held between the first substrate and the second substrate, and includes a first region located immediately above the pixel electrodes, and a second region located immediately above the pixel electrodes. And comprising
When the refractive index anisotropy of the liquid crystal layer is Δn, the thickness of the liquid crystal layer is d, and the retardation value of the liquid crystal layer is defined by Δn · d, the retardation value of the first region is A liquid crystal display device characterized by being smaller than the retardation value of two regions.   2. The liquid crystal display device according to claim 1, wherein a thickness d <b> 1 of the liquid crystal layer in the first region is smaller than a thickness d <b> 2 of the liquid crystal layer in the second region.   The liquid crystal display device according to claim 2, wherein at least one of the first substrate and the second substrate includes a protrusion. The first substrate further includes a source line extending in a substantially straight line and a gate line extending in a direction substantially orthogonal to the source line,
The liquid crystal display device according to claim 3, wherein the protrusion is arranged linearly or partially directly above the source line and substantially parallel to a direction in which the source line extends.   The liquid crystal display device according to claim 2, wherein the first substrate includes an insulating first protrusion disposed between the pixel electrodes and protruding toward the second substrate.   The said 1st board | substrate is provided with the columnar spacer which forms a cell gap between the said 2nd board | substrate, The height of a said 1st protrusion is lower than the height of the said columnar spacer, The Claim 5 characterized by the above-mentioned. The liquid crystal display device described.   6. The liquid crystal display device according to claim 2, wherein the second substrate includes an insulating second protrusion that is disposed immediately below the black matrix and protrudes toward the first substrate.   The liquid crystal display device according to claim 7, wherein the second protrusion is a laminate of the color filters.

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